1. Field of the Invention
This invention relates to a photographic paper, more particularly to a photographic paper which can be attached to the surface of a desired object and a process for producing the same.
2. Description of the Prior Art
Generally a photographic paper is composed of a support base, a resin (polymer) layer containing a light reflective material and an emulsion layer laminated in this order, or is composed of a support base, a resin layer containing a light reflective material, a primer layer and an emulsion layer laminated in this order. A color image or a black-and-white image is formed on the emulsion layer by printing the image on the phototgraphic paper. The image formed on the emulsion layer is sharply defined by the light which is reflected by the light reflective material, for example titanium dioxide (TiO.sub.2), contained in the resin layer and by the support base.
The support base is generally formed of a paper of substantial thickness so as to protect the photographic paper from being broken or folded. Accordingly, when the photographic paper on which an image has been formed is attached to the surface of an object such as a notebook the total thickness of the object becomes undesirably large. Further, since the support base is liable to curl, it is rather difficult to bring the whole area of the surface thereof into sufficient contact with the surface to which the photographic paper is to be attached. In the conventional photographic papers, the resin layer is firmly adhered to the support base so that the photographic paper will not be easily damaged in handling or storage and, accordingly, if the support base should be forcibly removed from the photographic paper, the resin layer and the emulsion layer would be damaged and, accordingly, the image formed on the emulsion layer would also be damaged.
It has previously been found that the adhesion strength, that is, the peeling strength between the resin layer and the support base can be adjusted by controlling the temperature of the polymer at the time the polymer is cast on the support base to form the resin layer and, accordingly, that a photographic paper having a support base which can easily be peeled off from a resin layer after an image is formed on the emulsion layer can be obtained without providing a release agent layer between the support base and the resin layer. Japanese Patent Application No. 41078/1977 discloses such a photographic paper, that is a photographic paper having a support base which can easily be peeled off from a resin layer, and which comprises a support base, a resin layer containing a light reflective material and an emulsion layer laminated in this order. In the photographic paper disclosed in Japanese Patent Application No. 41078/1977, the support base is peeled off from the resin layer after an image is formed on the emulsion layer. After the support base is removed, the resulting thin resin-emulsion composite can conveniently be attached to the surface of a desired object. Also, the photographic paper disclosed in the aforesaid patent application is simple in structure in comparison with a photographic paper having a release agent layer provided between a support base and a resin layer and, accordingly, can be manufactured at a low cost. In this photographic paper, after the support base is removed, an adhesive layer is formed on the lower surface of the resin layer to attach the resin-emulsion composite to the surface of a desired object.
However, the aforesaid photographic paper to be attach to the surface of a desired object which cmprises the resin-emulsion composite and the adhesive layer provided on the lower surface of the resin layer has a defect in that the quality of the image displayed thereby is inferior to that displayed by the conventional photographic paper having a support base. The defect is caused by the fact that the photographic paper does not have a support base. That is, in a photographic paper, it is the function of the support base not only to support the resin layer and the emulsion layer but also to work together with a resin layer containing a light reflective material to enhance the vividness of the image displayed. For this reason, white paper having good reflectance is employed in the conventional photographic paper as a support base. Naturally, the deterioration of image quality caused by attaching the aforesaid photographic paper having no support base to the surface of an object can be minimized by proper selection of the object to which the photographic paper is attached. However, this greatly narrows the range of practical application of the photographic paper.